Effect of Bandwidth on Wideband-STAP Performance

A wideband signal occupies a finite bandwidth that is significant compared to its carrier frequency. As a result when transmitted, its returns cause bandwidth dispersion across the antenna. It is shown here that the effect of the finite bandwidth is to introduce a set of uncorrelated return signals for every physical scatter in the field. Further, each such uncorrelated return contains a set of coherent signals with different directional and Doppler components that result from a jittering effect both in angle and Doppler domain. As a result, adaptive clutter cancellation using traditional processing schemes does not work well. Although in principle it is possible to correct these decorrelating effects by 3D space-time adaptive processing (STAP), the present day methods are quite costly and difficult to implement. In addition to the new wideband signal modeling framework mentioned above, we outline a hierarchical processing scheme which has the potential for dramatically reducing both processing and sample support burdens.